Ch 48 (test 1) Flashcards
where are free nerve endings found
skin and deep tissue and viscera
can free nerve endings adapt
very little
what chemicals cause pain stimuli
enodgenous–bradykinin, K ions, histamine, proteolytic enz.
what kind of sensory fibers are pain receptors
fast pain–A delta
slow pain–C
what layer is the lamina marginalis found in
layer 1
what layer is the substangia gelatinosa found
layer 1 and 2
where in the cord are cell bodies located
gray matter
where in the cord are myelinated axons located
white matter
what pathway does fast pain take in the cord
neospinothalamic pathway
describe the neospinothalamic pathway
- synapse in lamina 1
- 2nd order decussates in cord and up through anterolateral column to thalamus
- synapse in thalamus
- 3rd order to SSA1
what pathway does slow pain take in the cord
paleospinothalamic pathway
describe the paleospinothalamic pathway
- 1st order neurons synapse in lamina 1, 2 and 3 and/or 5
- 2nd order decussates in cord
- travels up anterolateral column to reticular formation/thalamus (brain stem)
pain suppression of the brain and cord are done by what system
analgesia system
describe how the analgesia system works
- AP generated in periventricular nuclei and periaqueductal gray
- AP sent to nucleus raphe magnus
- AP sent down cord to the inhibitory neuron, enkephalin
- inhibits excitatory pain receptor neuron
pain in part of the body that is distant to the area where the pain occurs
referred pain
why is visceral pain felt on the surface of the skin
synapse on same 2nd order neuron
3 causes of visceral pain
Ischemia
cramps
overdistention
what is ischemia
lack of oxygen, releases endogenous chemicals
what are cramps
smooth muscle contractions
what is overdistention
stretchingo fvisceral tissure (ex–full bladder)
why is visceral pain difficult to localize
1-no input from visual cortex
2-transmitted by 2 pathways
what 2 pathways is visceral pain transmitted by
true visceral–referred pain
parietal pathway–lacalized directly at area via from peritoneum
what are 3 main causes of headaches
1-tuggin on venous sinuses
2-stretching the dura mater
3-damage to blood vessels in meninges
What pathways do the somatic senses (mechanoreceptive, thermoreceptive, and pain) use
mechano–DC-ML, slight anterolateral
thermo–antero
pain–antero
what kind of nerve endings do warmth receptors use
free nerve endings (type C)
what kind of nerve endings do cold receptors use
free nerve endings (type C) unidentified receptor (type A delta)
what kind of nerve endings do heat/cold pain receptors use
free nerve endings (type C)
do thermoreceptors adapt quickly
yes–to change in temp and constant temp
